Method for protecting metals against corrosion and non-polluting reactive composition therefor

ABSTRACT

The invention concerns a method for protecting metal products against corrosion, characterised in that it consists in applying directly on the metal products, that is without prior treatment, a composition consisting at least of a film-forming binder, at least a corrosion inhibiting additive reactive with metal and at least an oligomer additive bearing phosphonic acids. The inventive composition is characterised in that it comprises a film-forming binder, at least a corrosion inhibiting additive reactive with metal and at least an oligomer additive bearing phosphonic acids.

The present invention concerns novel macromolecular compounds, theirsynthesis and their use in mixture with a binder, particularly forpaints usable for protecting metal surfaces against corrosion.

Polymers or copolymers bearing phosphonate groups or fluorine groups arealready known. Substances of this kind, described more particularly inBE Pat. 09400881, are obtained from a halogenated polymer and/orcopolymer activated by at least one peroxide and/or hydroperoxidefunction, to which at least one phosphonate chain is attached by meansof an unsaturated monomer.

The substances described in said patent do protect metal surfaces, butthey have many disadvantages.

A first disadvantage of the substances described in the prior art isthey must be synthesized from a base material such as a halogenatedpolymer and/or copolymer of the type of poly(vinylidene fluoride)(PVDF), which is available commercially. Commercial chemicals, however,are highly elaborated and therefore very expensive, thus increasing thecost of the end product.

Another disadvantage is that the polymer and/or copolymer isthermoplastic and therefore sensitive to heat.

A third disadvantage is that activation techniques employing electronbeams or ozone are onerous processes.

Yet another disadvantage is that with the materials described in theabove-cited document, it is impossible to modulate the protection periodof the metal.

In industry, protection for metal parts is desired as a temporarymeasure, prior to use, or for longer periods of time, depending on thesubsequent use of the parts. For instance, it is desirable to be able tostore protected parts for periods that can vary by a few months and thenbe able to use them.

Also known are polymers or copolymers bearing phosphonate groups,film-forming groups and crosslinkable groups.

The state of the art with regard to the synthesis ofphosphorus-containing copolymers can be summarized as follows:

phosphate monomers, which are acrylates of the following formula

described in the patents

U.S. Pat. No. 5,378,291 (Nihon Parkerizing Co.),

PCT WO 88/02 382 (DuPont de Nemours),

EPA 0 221 498 (Johnson et Son),

EPA 0 376 591 (Rohm and Haas),

EPA 0 458 245 A1 (Nippon Paint Co.).

The disadvantages of these materials are, first, their instability withregard to hydrolysis (C—O—P bond) and the fact that their double-bondreactivity functionality is higher than 1, which naturally excludes themfrom the domain of solvated paints.

phosphonated monomers, which are of several types:

which are described in the patents:

DP 2 232 711 (Stauffer Chem.)

EPA 0 069 31.8 (Hoechst)

Their principal disadvantage, apart from price, is their very poorpolymerization reactivity.

styrene monomers:

which are described in U.S. Pat. No. 3,051,740 (Monsanto).

The disadvantage of these materials is their intricate and costlysynthesis.

acrylate monomers

described in the patents:

EPA 0 278 029 (Dow Chemical)

U.S. Pat. No. 4,658,003 (Dow Chemical),

which may result in chemically unstable end products. In addition, theuse and disposal of aldehydes, especially formol, which is a necessityfor synthesis, are deprecated for environmental reasons.

fluorophosphonates

CF₂═CF—(CF₂)_(x)—PO(OH)₂

described in the patent EPA 0 398 250 (Daikin).

Their disadvantages are poor radical-polymerization reactivity and verycomplex preliminary synthesis.

Ordinary paints are composed of a film-forming agent, which forms a filmof one or more solvents, pigments and/or colorants on the metal andwhich hardens at ambient temperature or above. These paints are appliedto the metal directly when it is free of oxidation, impurities and/ordirt or after it has undergone an anticorrosion treatment, for examplephosphating followed by chromating. The chemicals used for suchanticorrosion treatment contain toxic heavy-metal derivatives and highlyvolatile solvents. Such treatments are therefore harmful both to humanhealth and to the environment.

The following patents can also be cited as belonging to the prior art:

EP 0 516 346, which describes a method for synthesizing certain telomersin an aqueous medium and provides for phosphorus-containing additives.

EP 0 277 711, which cites a few substituent phosphonic groups ofpolyesters somewhat randomly, without any specific intentions; moreover,it is primarily amines rather than phosphonates that are being sought.

EP 0 035 316, which alludes to mineral zinc phosphate additives ratherthan organic phosphonates.

The present invention concerns a treatment method and a composition thathas the property of ensuring anticorrosion protection and adherence tometal but eliminates the need for prior treatment, particularly theanticorrosion treatments of phosphating and chromating.

To this end, the invention concerns a method for protecting metalarticles against corrosion, characterized in that it consists inapplying to the metal articles directly, i.e., without prior treatmentof any kind, a composition formed, at the least, of a film-formingbinder, at least one corrosion-inhibiting additive reactive with metal,and at least one oligomer additive bearing phosphonic acids.

According to other characteristics of this method:

metal articles to be treated whose surfaces are excessively oxidized butnot scaled are subjected to coarse brushing to reduce their surfaceoxidation to a low value that is not necessarily zero, and thecomposition is then applied to them;

metal articles to be treated whose surfaces are excessively greasy aresubjected to coarse cleaning to reduce their surface grease to a lowvalue that is not necessarily zero, and the composition is then appliedto them.

The invention also concerns a composition for protecting metal articlesagainst corrosion, comprising a binder and at least one additive,characterized in that it comprises a film-forming binder, at least onecorrosion-inhibiting additive reactive with metal, and at least oneoligomer additive bearing phosphonic acids.

According to other characteristics of this composition:

it further comprises one or more pigment additives;

it further comprises one or more wetting agents;

the wetting agent includes at least one component selected from thefollowing:

ethoxylated alkyl and aryl phosphonates,

fluorocarbon derivatives,

perfluoroalkylated ammonium sulfonate,

perfluoroalkylated potassium sulfonate,

perfluoroalkylated alcohol amino sulfonate

perfluoroalkylated acrylate

the additives bear a polymer chain compatible with the binder;

the additives are statistical copolymers having blocks or grafts thatbear sequences or grafted components compatible with the binder;

the additives are copolymers of at least one monomer compatible with thebinder and of at least one phosphonated monomer;

the monomer compatible with the binder is chain-polymerizable and isselected from methacrylic acrylic, styrene, vinyl chloride, vinylfluoride and vinyl ester monomers;

the monomer compatible with the binder is selected from polycondensablemonomers, diols and epoxide diacids;

it includes phosphonic acid groups;

the reactivity additive is a phosphonate or a phosphate whose molecularchains are either hydrocarbonated, fluorinated or chlorofluorinated;

the reactivity additive includes at least one component selected from:

alkyl acid phosphones and phosphonates,

phosphoric acids,

aminotrimethylene phosphonic acid,

1-hydroxyethylidene-1-1-diphosphonic acid,

ethylene diamine tetramethylene phosphonic acid,

hexamethylene diamine tetramethylene phosphonic acid,

diethylene triamine pentamethylene phosphonic acid.

The invention will be better understood from the following detaileddescription, provided solely as an indicative and nonrestrictiveexample. The following substances may be cited among those used in theformulations of the inventive composition:

A) Film-forming Binders

These are homopolymers and copolymers obtained from unsaturated monomersused in paints. Said monomers are vinyl, acrylic, styrene, dienic,halogenated or nonhalogenated monomers well known to those skilled inthe art.

In the case of reactive binders, the reactivity is most often suppliedby carboxylic acid groups, but it can also be supplied by phosphonategroups, which makes the binders more compatible with the additives ofthe invention.

The phosphonic groups are supplied by monomers that will be describedbelow in connection with the reactive additives.

B) Reactive Additives

These are molecular or macromolecular compounds of low molar mass (lessthan a few thousand, and preferably close to one thousand).

In addition, these additives all bear phosphorus-containing groups(preferably phosphonic groups), and their primary purpose is to reactwith metal at its surface. At least one acid function (P—OH) istherefore necessary.

Three major classes of additives can be contemplated:

Phosphonated alkanes or alkenes

These substances have one or more phosphonic groups at their chain endsand/or within the chain.

The following formulas are possible:

Monophosphonic compounds:

C_(n)H_(2n+1)—Q—PO(OR)₂

C_(n)F_(2n+1)—C₂H₄—Q—PO(OR)₂

where Q=nil or SC_(x)H_(2x) and x=2.3

H—(M)_(n)—PO(OR)₂

M=C₂F₄, C₂F₃Cl, C₃F₆, C₂F₂H₂

R=H or alkyl in all cases.

diphosphonic and telechelic compounds

(RO)₂OP—Z—PO(OR)₂

Z′—N[CH₂—PO(OR)₂]₂

where: R=H, alkyl

Z′ similar to the groups previously described with regard tomonophosphonic compounds,

Z=alkylenes or arylenes derived from nonconjugated dienes(divinylbenzene or 1-5-hexadiene, for example)

polyphosphonic compounds:

Structures may contain plural phosphonic groups (≧2). For example, withPBHT as the starting material, the following formula is obtained:

where R=H or alkyl

References:

Polymer Bulletin 41, 145-151 (1998),

Grafting phosphonated thiol on hydroxy telechelic polybutadiene (BernardBoutevin, Yves Hervaud, Gérard Moutedous) [citation sic].

All-phosphonic statistical telomers and cotelomers

The structures are as follows, respectively:

R—M₁)_(n)—X where n≧2

and

R—(M₁)_(x)—(M₂)_(y)—X where n≧2 (statistical)

The phosphonic groups are supplied either by vinyl, allyl, acrylic orstyrene monomers or by telogenic agents (R—X) of the phosphonate type(alkyl or haloalkyl).

The M₂ comonomers are all those generally used in copolymerization,which are well known to those skilled in the art; some examples are:

where R=H, alkyl from vinyl acetate

where R=H, alkyl from allyl acetate

Starting with methyl methacrylate (MMA) and phosphonated methylmethacrylate (MAPHOS), radical seeding results, after hydrolysis, instatistical copolymers of the following formula:

Block phosphonic cotelomers.

Recent advances in controlled radical polymerization have providedaccess to block copolymers (see “Synthesis of Block Copolymers byRadical Polymerization and Telomerization,” Advances in Polymer Science,Vol. 127, pp. 88-112, B. Améduri, B. Boutevin and Ph. Gramain, EcoleNationale Supérieure de Chimie de Montpellier, URA 1193 CNRS 8, rueEcole Normale, 34053 Montpellier Cedex France).

In the case of methacrylic derivatives, two methods have been used:

atom-transfer radical polymerization (ATRP).

Example with MMA and MAPHOS:

from thiuranes, cotelomers similar to the foregoing are obtained asfollows:

(Living radical polymerization of MMA in the presence ofpiperidinodithiocarbamate derivatives as photoiniferters (cf. DenisBertin, Bernard Boutevin, Philippe Gramain, Jean-Marc Fabre and ClaudeMontginoul

Laboratoire de Chimie Appliquée, UPRES A 50760, Ecole NationaleSupérieure de Chimie de Montpellier—Laboratoire de Chimie StructuraleOrganique, UPRES A 50760, Université Montpellier II, Eup. Polym. J. Vol.34, No. 1, pp. 85-90, 1998, Elsevier Science Ltd.) [citation sic]

C) Anticorrosion Additives

modified zinc, calcium or strontium orthophosphate,

modified zinc or aluminum orthophosphate,

modified organic zinc orthophosphate,

modified zinc or molybdenum orthophosphate,

phosphate, zinc silicate, modified hydrated aluminum,

modified zinc, calcium, aluminum or strontium polyphosphate,

etc.

D) Other Additives

Mineral Pigments:

Aluminum, mica, glass flakes, talc, titanium oxide, iron oxides, bariumsulfate, chrome green, graphite, silicas, silicates, etc.

Organic Pigments:

Quinacridones, pyrazolone, isonidoline, quinophthalone, phthalocyanine,indatone, etc.

Surfactants:

ethoxylated alkyl and aryl phosphates,

fluorocarbon derivatives,

perfluoroalkyl ammonium sulfonate,

perfluoroalkyl potassium sulfonate,

perfluoroalkyl aminoalcohol sulfonate,

perfluoroalkyl acrylate.

The invention will be better understood from the following detaileddescription, provided solely as an indicative and nonrestrictiveexample.

The invention simplifies the use of paints and coatings and utilizessynergies among the properties of the binders and additives used. Inparticular, if the binder has good barrier properties and the additivehas very good adherence to metal, the resulting materials have excellentcorrosion-resistance properties.

Since interpolymer compatibility is a relatively rare characteristic,the polymers that are combined are of the same kind or are very similar,i.e., differing with respect to molecular size or composition, which inmost cases is related to the composition of the binder, although theycan have some new units.

Phosphonated monomers bear a polymerizable double bond and a phosphonicgroup, joined to the side chain of the monomer by a C—P bond. Similarly,polycondensable monomers have a phosphonate group connected to the sidechain of the monomer by a C—P bond.

Examples include styrene monomers of the formula:

in which R and R′ are similar or different and equal.

Other examples that can be cited are acrylic monomers of the formula:

in which R and R′ are similar or different.

Q=

CH₂—CH₂

(CH₂)₂—S—(CH₂)₃

Reaction additives can also be obtained by the chemical modification ofcommercial oligomers such as PBHT, from Atochem,

where Z=nil or S—CH₂—CH₂.

All the phosphonated additives described above are effective only inacid form.

The chemical transformation of phosphonic esters, whether on monomers oron copolymers, is well known to those skilled in the art and can beperformed, in an acidic or basic medium, to obtain phosphonic monoacids,or, using halosilanes, to prepare phosphonic diacids according to thefollowing reaction:

The following description, provided in regard to nonrestrictivelyannexed examples, will furnish a better understanding of how theinvention can be put to use.

EXAMPLE 1 Synthesis of a 55/45 MMA/MAPHOS Copolymer

Let MMA represent methyl methacrylate

and MAPHOS phosphonated methacrylate

prepared according to the method described by C. Brondino (Thesis,Montpellier, 1996).

A one-liter three-necked flask provided with a water-based coolant,nitrogen bubbling and a dropping funnel was charged with 20.0 g (0.2mol) of MMA, 44.4 g (0.2 mol) of MAPHOS and 400 ml of THF. The droppingfunnel was charged with 1.968 g of AIBN [2,2′-azobisisobutyronitrile]dissolved in 100 ml of THF.

The reaction mixture was degassed for 15 min and heated to 70° C. 30 mlof seeding solution were then added dropwise. Two hours later, another30 ml of seeding solution were added dropwise. The rest of the seedingsolution was then added dropwise after 4 h.

After 6 h of reaction, the reaction mixture was precipitated in 4 l ofpentane. The copolymer thus collected was filtered and was thendissolved in 200 ml of dichioromethane. The mixture was againprecipitated in 4 l of pentane, and after filtration a fine, white,dusty, very hygroscopic powder was obtained. This was dried in a balloonflask under high vacuum for 4 h. 59.8 g of copolymer was obtained, for ayield of 93%.

¹H NMR analysis (CDCl₃ confirmed the composition of the copolymer, whichcontained 54% MMA and 46% MAPHOS.

EXAMPLE 2 Hydrolysis of a 55/45 MMA/MAPHOS Copolymer

A one-liter three-necked flask provided with a water-based coolant,nitrogen bubbling and a dropping funnel was charged with 59.8 g (0.37mol) of the copolymer from Example 1, dissolved in 500 ml ofdichloromethane. The solution was degassed for 15 min; this was followedby the dropwise addition of 53 ml (0.41 mol) of bromotrimethylsilanefreshly distilled under nitrogen. The mixture was stirred at ambienttemperature for 3 h.

At the end of the reaction, the solvent was evaporated with a Rotavapor,and an excess of methanol (500 ml) was then added. The mixture wasstirred at ambient temperature for 3 h and the solvent was evaporatedagain. The end product collected was 58.8 g of hydrolyzed copolymer inthe form of a yellowish paste.

EXAMPLE 3 Synthesis of an MMA/phosphonated Styrene Copolymer

Let MMA stand for methyl methacrylate, the formula for phosphonatedstyrene being:

These substances have already been described. See Bernard Boutevin*,Bachar Hamoui, Jean-Pierre Parisi and Bruno Ameduri, “Homopolymerizationand copolymerization of salt formed from a new diethyl styrenicphosphonate monomer,” Eur. Polym. J. 32/2 (1996), 159-163, Copyright©1996, Elsevier Science Ltd., printed in Great Britain, All rightsreserved, 0014-3057(95)00132-8-0014-3057/96, $15.00+0.00.

EXAMPLE 4 Grafting of Phosphonated Thiol, HS—(CH₂)₃—PO(OEt)₂, on aStyrene-butadiene Copolymer

A 3-liter flask was charged with 10 g of Finapren 502, 2.76 g ofphosphonated thiol and 0.1 g of benzophenone, the whole dissolved in 700ml of THF. The solution was degassed with nitrogen for 15 min and thereaction mixture was irradiated with UV for 24 h.

The solution was found to have formed a gel, which was redissolved in atotal volume of THF of 2.5 1. At the end of the reaction, the solutionwas concentrated to 700 ml and precipitated in 4 l of methanol. Thewhite precipitate collected was filtered, rinsed and dried under vacuum.This resulted in isolation of the grafted polymer in the form of anelastic gum.

¹H NMR analysis (CDCl₃) confirmed the structure of the expectedmaterial.

Elementary analysis was used to determine the percentage of phosphorusin the grafted copolymer. The value in this case was 2%. The graftingefficiency was therefore 50%.

EXAMPLE 5 Synthesis of a Copolymer Containing an Epoxide Group

A 3.54-liter autoclave equipped with a stirrer was charged with 2l ofacetonitrile, 1 mol 2-hydroxcyethyl vinylether, 4 mol2-(dimethoxyphosphonate) ethylvinylether and 22 g of benzoyl peroxide.The mixture was degassed under vacuum and 5 mol chlorotrifluoroethylenewere added. The mixture was heated to 95° C., causing the pressure toincrease to 30 bars. The pressure had fallen to 10 bars at the end of 6h. The reactor was cooled and was degassed to remove the unreactedchlorotrifluoroethylene. A copolymer solution was obtained that yieldednearly 38% dry extract. This copolymer contained fluorine motifssupplying 19 to 21% fluorine (elementary analysis).

EXAMPLE 6 Synthesis of the Copolymer From Example 5 With Silyl Groups

A 3-liter reactor was charged with 160 g of the copolymer obtainedaccording to Example 5, in acetonitrile, and containing 0.5mole-equivalent of OP(OCH₃)₂. One mole of bromotrimethylsilane was addedat ambient temperature during 2 h. After reaction and evaporation of thesolvent, proton nuclear magnetic resonance (¹H-NMR) revealed O—Si(CH₃)₃groups on the copolymer, substituted for the OCH₃ groups.

This polymer can be stored as is, or it can be hydrolyzed with excessmethanol. The latter method yields a copolymer containing acidphosphonate structural units: —PO(OH)₂.

EXAMPLE 7

The reactor was charged with 160 g of the copolymer from Example 5 andone mole of chlorotrimethylsilane was added in place of thebromotrimethylsilane. The majority component obtained was thephosphonate derivative bearing a methyl-ester function and a sylilfunction. After hydrolysis, the resulting copolymer contained mixedphosphonate acid-ester structural units of the formula: —PO(OCH₃)(OH).

EXAMPLE 8 Synthesis of the Ammonium Salt of the Copolymer From Example 6

The reactor was charged with 140 g of the copolymer obtained accordingto Example 2, containing approximately 0.5 mole-equivalent of —PO(OH)₂;to this was added one mole of cyclohexylamine, i.e., 181 g, and themixture was left to react for one hour. Infrared analysis of the productdemonstrated disappearance of the OH bands.

EXAMPLE 9

The reactor was charged with the same constituents as in Example 5, butone mole of chlorotrifluoroethylene was replaced with one mole ofCH₂═CH—(CH₂)₂—-C₈F₁₇.

The reaction was then carried out under the same conditions as inExample 5. The end product had a fluorine concentration, determined byelementary analysis, of about 31%. This copolymer can be treated by thesame method as that of Examples 6 to 8.

EXAMPLE 10

The compounds were synthesized according to Examples 5 to 8, but thehydroxyethyl vinyl ether was replaced with dimethoxy-methylsilylpropylvinyl ether of the formula CH₂═CH—O—(CH₂)₃—Si(CH₃)(OCH₃)₂.

EXAMPLE 11

A reactor was charged with approximately 180 g of the copolymeraccording to Example 10 and containing 0.5 mole-equivalent of—PO(OCH₃)₂. One mole chlorotrimethylsilane was added and the mixture wasleft to react for two hours at ambient temperature. As in Examples 2 and3, ¹H NMR then revealed a signal indicating the presence of OSi(CH₃)₃groups.

EXAMPLE 12

Under the same operating conditions as in Example 5, the reactor wascharged with a mixture composed of one mole of allyl alcohol and onemole of allyl diethylphosphonate. After cooling, to this was added agaseous mixture composed of vinylidene fluoride andchlorotrifluoroethylene in a ratio of 6.5:1.5. Under the same pressureconditions as in Example 5, after 6 h of reaction and degassing, afluorinated copolymer was obtained whose fluorine concentration,measured by elementary analysis, was about 40%.

EXAMPLE 13

Under the same operating conditions as in Example 5, the reactor wasfirst charged with a mixture composed of 1 mol allyl hydroxyethyl etherand 1 mol diethyl vinylphosphonate. After degassing and cooling, 6 molvinylidene fluoride and 2 mol hexafluoropropylene, CF₃—CF═CF₂, wereadded. After 5 h of reaction, a copolymer containing approximately 48%fluorine was obtained.

EXAMPLE 14

Under the operating conditions of Example 5, the reactor was firstcharged with 1 mol diethyl allylphosphonate, 1 mol allyl alcohol and 1mol vinyl acetate. After cooling and degassing, 6 molchlorotrifluoroethylene were added. After 6 h of reaction, a copolymercontaining approximately 31% fluorine was obtained.

EXAMPLE 15

A Hasstelloy autoclave reactor with a capacity of 1000 ml was chargedwith:

234 g (1.69 mol) of phosphonate, HPO(OEt)₂

2.5 g (1.71·10⁻² mol) of di-tert-butyl peroxide,

200 g (4.93 mol) of acetonitrile and 108 g (1.69 mol) of vinylidenefluoride (VF₂).

Five hours of reaction at 140° C. yielded a telomer mixtureH(—CF₂—CH₂)_(n)—PO(OEt)₂ with a DP_(n) of about 3.0 and a VF₂ conversionratio on the order of 90%.

EXAMPLE 16

Under the same conditions described in Example 15, the reaction wascarried out with chlorotrifluoroethylene (CTFE). 1.97 g (1.69 mol) ofCTFE were added. The telomer mixture obtained,H—(CFCl—CF₂)_(n)—PO(OEt)₂, bad a DP_(n) of about 2, and the CTFEconversion ratio was 78%.

EXAMPLE 17

In accordance with Example 15, the phosphonate was dimethyl hydrogenphosphonate, HPO(OCH₃).¹

¹TRANSLATOR'S NOTE. Discrepancy in formulas sic; the subscript “2” ismissing in the first occurrence.

EXAMPLE 18

In accordance with Example 16, the phosphonate was dimethyl hydrogenphosphonate, HPO(OCH₃)₂.¹

¹TRANSLATOR'S NOTE. Discrepancy in formulas sic; the subscript “2” ismissing in the first occurrence.

EXAMPLE 19

The substances from Example 15 were hydrolyzed, either by means ofmethanol after silylation by a halosilane of the type XSi(CH₃)₂, whereX=Cl, Br, or by the action of hydrochloric acid.

Thus, commencing with 50 g of HCF₂—CH₂—PO(OEt)₂ monoadduct and 39.4 g ofBrSi(CH₃)₃ added dropwise in the presence of CH₂Cl₂ (solvent) and after2 h of agitation, 50 ml of methanol were added to the medium. Afterdistillation, 34.7 g of a monoacidic substance, H—CF₂—CH₂—PO(OH)(OEt),were obtained.

EXAMPLE 20

The substances from Example 16 were hydrolyzed as described in Example19.

A 100-ml balloon flask provided with a coolant was charged with 4.00 g(1.57·10⁻² mol) of monoadduct dissolved in 20 ml of toluene, to whichwere added 8 ml of 12N HCl (9.6·10⁻² mol; 6 eq. of HCl to 1 eq. ofester). The solution was maintained at solvent reflux (120° C.) for 12h.

After cooling of the solution, the toluene was evaporated and thesolution was washed twice with 50 ml of distilled water. It wasreconcentrated. A white solid weighing 4.44 g was recovered from theaqueous phase after concentration and oven-drying. NMR analyses revealedcleavage of 75% of the “phosphonic ester” groups.

EXAMPLE 21

A 100-ml flask provided with a coolant was charged with 6 g of PBHTR-20, 4 g of thiol HS—(CH₂)₃—PO(OEt)₂, 0.18 g of AIBN and 60 g of THF(solvent). After 4 h of reaction at 70° C. and after treatment of theproduct, NMR analyses revealed a grafting ratio of 19%. The graftedproduct therefore contained 2.6% phosphorus. These reactions havealready been described:

Ref.: Bernard Boutevin, Yves Hervaud and Gérard Molédous, “Graftingphosphonated thiol on hydroxy telechelic polybutadiene,” PolymerBulletin 41 (1998), 145-151.

EXAMPLE 22

Synthesis of the MMA/MAPHOS Block Copolymer.

Step 1:

MMA was polymerized with thiuram.

The result was compound (A), of the formula:

with a number molecular weight of approximately 20,000.

Step 2:

Photochemical polymerization of compound (A) was performed with MAPHOS,yielding copolymer (B) of the formula:

7 MAPHOS per chain were added (p therefore equalled 7).

The number molecular weight was approximately 21,000 (structure checkedby NMR).

Step 3:

Compound 3 was hydrolyzed by means of BrSi(Me)₃, then CH₃OH.

EXAMPLE 23

A 1000:1:2 mixture of styrene, dicumyl peroxide and “Tempo” (piperidinenitroxyl) was introduced.

The mixture was maintained at 120° C. for 8 h. An aliquot was analyzedby GPG (gel permeation chromatography), which revealed the formation ofa polystyrene with a molecular weight of 45,000, fairly close to theexpected value of 50,000.

To the reaction mixture was added CH₂═CH—φ—CH₂—PO(OC₂H₅)₂, in molarproportions of 1 mol polystyrene to 100 mol phosphonated monomer. Themixture was maintained at 120° C. for 10 h, resulting in completeconversion to a phosphonated styrene derivative.

The final polystyrene equivalent molecular weight was 68,000. ¹H NMRconfirmed the presence of about 5 styrene motifs to 1 phosphonate motif(integration of the —O—CH₂—CH₃ group) with respect to all aromaticprotons.

The esters were hydrolyzed with ClSiMe₃ to obtain the correspondingdiacid.

EXAMPLE 24

Synthesis of crosslinkable phosphonates of the following formula

The alcohol C₁₂H₂₅OH was added mole by mole to POCl₃ in chloroform inthe presence of triethylamine to trap the hydrochloric acid formed.After two hours of reaction, the unsaturated alcohol C₁₈H₃₅OH was added,and after two hours of reflux in CHCl₃, the mixture was hydrolyzed.After extraction, a monoacid with an acid index corresponding to theabove formula was isolated.

Any of the following three preparations can be used for this example:

Preparation A

From the compound obtained in Example 24, an aqueous solution of thefollowing composition is prepared:

10 parts compound of Example 24

1 part nonyl phenoxyacetic acid

a sufficient quantity of ethanolamine to yield 8.5≦pH≦9.5

6 parts propylene glycol monomethyl ether

water to make 100 parts.

This solution was applied to steel surfaces, and after removal of thewater, protection in accordance with ASTM Standard D 1735-62 wasobtained on exposure to a moisture-saturated atmosphere at 37.8° C. Thecorrosion in accordance with ASTM Standard D 610-68 was estimated atGrade 10 after one week. This was equivalent to a complete absence ofcorrosion, whereas a steel specimen not treated in this manner exhibitedGrade 1 corrosion, corresponding to corrosion of 50% of the surface,after only 24 h.

The compound according to Example 24 provides temporary protection for168 h, since it is not crosslinked. It can be removed from the steel tomake way for subsequent treatment, for example the steel can be rolled,formed, transformed by cutting, stamping, welding, etc.

Preparation B

5 parts compound of Example 24

5 parts 50% styrene-acrylic copolymer

1 part nonyl phenoxyacetic acid

dimethylaminoethanol in sufficient quantity to yield 8.5≦pH≦9.5

6 parts propylene glycol monomethyl ether

water to make 100 parts

This composition resulted in Grade 10 on galvanized steel after sixweeks of exposure. Without treatment, an identical surface showed Grade1 corrosion after one week of exposure.

Preparation C

5 parts compound of Example 13

5 parts 50% styrene-acrylic copolymer

1 part nonyl phenoxyacetic acid

cyclohexylamine in sufficient quantity to yield 8.5≦pH ≦9.5

2 parts substituted imidazole formiate

6 parts propylene glycol monomethyl ether

water to make 100 parts

Under the same test conditions as in Example 20, when applied togalvanized steel, this composition resulted in Grade 10 after ten daysof exposure.

Using the same composition, the corrosion test was performed byimmersion in a 3.5% NaCl solution: without protection, corrosion wasevident on a bare steel surface after 15 min. of immersion; after thecomposition had been applied, no corrosion whatsoever was observed after12 h of exposure.

This composition is a one that affords temporary protection and caneasily be removed by washing.

EXAMPLE 25

Epoxidation of the salt of the acid obtained according to Example 13.

To one mole of acid from Example 1 were added one mole of ammoniafollowed by 1.2 mol p-chloroperbenzoic acid, and reflux was maintainedfor one hour. The mixture was concentrated to 50% dry extract.

EXAMPLE 26

To the mixture obtained according to Example 14, acrylic acid was addedmole by mole and reflux was maintained for 8 h. After the addition of 1%hydroquinone, an acrylated substance was obtained.

EXAMPLE 27

Diethyl hydrogen phosphonate, HPO(OEt)₂, was added to 1-dodeceneaccording to the method described by Peleprat et al. The compoundC₁₂H₂₅PO(OEt)₂ was obtained in a yield of

This compound was hydrolyzed with bromotrimethylsilane according to themethod described by Hamoui et al. (Macromol. Chem. Phys., 1985, 1995[citation sic]). C₁₂H₂₅PO(OH)₂ was obtained in this manner.

This diacid was esterified in toluene under heat with a Dean Starksystem to remove the water, the esterification being done with analcohol of the formula C₁₈H₃₅OH, to yield a compound of the followingformula:

This compound was epoxided as in Example 14, and acrylation was thenperformed as in Example 25.

EXAMPLE 28

As in Example 16, diethyl hydrogen phosphonate, HPO(OEt)₂, was added toone mole of allyl glycidyl ether.

The following compound was obtained quantitatively:

The fatty acid C₁₈H₃₇CO₂H was added to this epoxide in the presence of10⁻² mol ethyl laurylamine to yield a compound of the following formula:

To the preceding compound was added acryloyl chloride, and a compound ofthe following formula was obtained:

which, when hydrolyzed with bromotrimethylsilane, quantitatively yieldedthe corresponding acid, of the following formula:

Either of the following two compositions can be used for long-termprotection on bare steel:

Preparation A

145 parts compound obtained in Example 28

220 parts polyvinyl difluoride grafted with hydroxyethyl acrylate

6 parts ammonia

167 parts rutile (titanium oxide)

33 parts red iron oxide

2.5 parts dispersant

33 parts diethylene glycol

2.5 parts antifoaming agent

68 parts melamine methylol

323 parts water

The characteristics of the composition are as follows:

8.6≦pH≦8.8

ratio of pigment to grafted polyvinyl difluoride=0.55:1.0

Ford No. 4 viscosity 45/50 seconds

% melamine: dry extract: 18.6

The composition is applied by spraying or after dilution.

The coating is baked for 10 min at 180° C. or 15 min at 150° C. Theresultant coating has a protection period of 500 h (resistance to salinemist measured according to AFNOR Standard×41.002).

The pencil hardness is F.2H.

The NFR 30038 adherence is 100%.

Preparation B

6 parts compound obtained in Example 28

5 parts vinyl-maleic copolymer

4 parts 9% polyvinyl alcohol

ammonia in sufficient quantity to yield 8.5≦pH≦9.0

1 part hydroxyethyl cellulose

1 part HLB 12 nonionic wetting agent

8 parts Zn₃(PO₄)₂, 2H₂O

water to make 100 parts

The density of the composition is 1.08 to 1.10.

The Ford No. 4 viscosity is 20 to 22 seconds.

The composition is sprayed on or applied as is.

Baking is performed for 15 min at 150° C. Long-term protection of steelis obtained, with a protection period of more than 500 h.

EXAMPLE 29

Commencing with the alcohol obtained in Example 17,

transvinylation was performed with butyl vinyl ether, using apalladium-containing catalyst as described in J. of Phys. Chem. 44(1989), 395, to yield the compound of the following formula:

This compound was hydrolyzed with BrSi(Me)₃ and ammonia to yield thedisalt of the following formula:

EXAMPLE 30

To the epoxide prepared in Example 14, cinnamic acid was added accordingto the method of Example 13.

A substance having the following formula was obtained:

Hydrolysis, performed as hereinabove, yielded a compound of thefollowing formula:

A composition according to the invention can also be in the form of anaqueous emulsion:

EXAMPLE 31

An aqueous emulsion of polyethylene was prepared from the followingconstituents:

Parts PE-AA AC 5120 copolymer  40 25% ammonia solution  8Dodecylphosphonic acid  4 Xanthan gum  1 Demineralized water 197

Synthesis of Dodecylphosphonic Acid

Dodecylphosphonic acid was prepared in two steps as follows:

A three-necked flask provided with a dropping funnel, an argon inlet anda distilling apparatus was charged with 49.8 g of bromododecane. Theassembly was placed in an inert atmosphere and heated to 130° C. 36.5 gof triethyl phosphite were then added dropwise through the funnel. After24 h of reaction, the remaining reactants were removed by distillationunder vacuum, resulting in the collection of 55.1 g of diethyldodecylphosphonate 1, i.e., a yield of 90%.

30.6 g of Compound 1 isolated in this manner were then dissolved in 500ml of dichloromethane. 30.6 g of bromotrimethylsilane (2 eq.) were thenadded in an inert atmosphere. The mixture was stirred at ambienttemperature for 3 h. The solvent was then evaporated, after which 500 mlof methanol were added. After 2 h of stirring at ambient temperature,the methonal was evaporated. A white solid was collected and was washedin ether and dried under vacuum 23.9 g of dodecylphosphonic acid 2 werecollected, for a yield of 95.6%.

Preparation of the Aqueous Emulsion of Polyethylene

A pressurized reactor was charged with Ethylene-Acrylic Acid copolymerAC5120, 25% ammonia solution and demineralized water. All thesecomponents were heated to 110° for 15 min with vigorous mechanicalagitation. The mixture was cooled rapidly in ice and the emulsion wasthen collected in the form of a completely homogeneous slurry with a pHof 10.

The aqueous emulsion of polyethylene was placed in a mechanicalagitator. Under gentle agitation, xanthan gum was added, followed bydodecylphosphonic acid. The agitation speed was gradually increased todissolve the additives fully in the emulsion.

What is claimed is:
 1. A composition for protecting metal articlesagainst corrosion, comprising: a film-forming binder, at least onecorrosion-inhibiting additive that is reactive with metal; and at leastone oligomer of at least one monomer that is compatible with the binder;and at least one phosphonated monomer; the monomer that is compatiblewith the binder being selected from the group consisting of: the chainpolymerizable monomers selected from the group connecting of:methacrylic acrylic, styrene, vinyl chloride, vinyl fluoride and vinylester monomers; and polycondensable monomers selected from the groupconsisting of: diols and epoxide diacids.
 2. A composition according toclaim 1, in which the oligomer of at least one monomer compatible withthe binder, and of at least one phosphonated monomer, includesphosphonic acid groups.
 3. A composition according to claim 2, in whichthe oligomer of at least one monomer compatible with the binder, and ofat least one phosphonated monomer is selected from the group consistingof: copolymers of methylmethacrylate and phosphonatedmethylmethacrylate; copolymers of methylstyrene and phosphonatedmethylmethacrylate; styrene-butadiene copolymers grafted with aphosphonated thiol; a copolymer of three monomers, of which the firstmonomer is selected from the group consisting of2-hydroxyethylvinylether and dimethoxy-methylsilylpropyl vinyl ether,the second monomer is selected from the group consisting of2-(dimethoxyphosphonate)ethylvinylether,2-(monomethoxyphosphonate)ethylvinylether and 2-(phosphonicacid)ethylvinylether, and the third monomer is selected from the groupconsisting of chlorotrifluoroethylene and CH₂═CH—O—(CH₂)₂—C₈F₁₇; acopolymer of allyl alcohol, allyl diethylphosphonate, vinylidenefluoride and chlorotrifluoroethylene; a copolymer ofdiethylallylphosphonate, allyl alcohol, vinyl acetate andchlorotrifluoroethylene; a copolymer of diethylphosphonate andvinylidene fluoride; a copolymer of diethylphosphonate andchlorotrifluoroethylene; a copolymer of dimethylphosphonate andvinylidene fluoride; a copolymer of dimethylphosphonate andchlorotrifluoroethylene; a copolymer of monoethylphosphonate andvinylidene fluoride; a copolymer of monoethylphosphonate andchlorotrifiuoroethylene; a copolymer of phosphonic acid and vinylidenefluoride; a copolymer of phosphonic acid and chlorotrifluoroethylene; acopolymer of hydroxytelechelic polybutadiene grafted withHS—(CH₂)₃—PO(OEt)₂; a copolymer of styrene and CH₂═CH—φ—CH₂—PO(OC₂H₅)₂;a copolymer of diethylallylphosphonate, allyl alcohol, vinyl acetate andchlorotrifluoroethylene and acrylic acid.
 4. A composition according toclaim 1, in which the corrosion-inhibiting additive reactive with metalis a phosphonate or a phosphate whose molecular chains are eitherhydrocarbonated, fluorinated or chlorofluorinated.
 5. A compositionaccording to claim 4, in which the corrosion-inhibiting additivereactive with metal comprises at least one component selected from thegroup consisting of: alkyl acid phosphones and phosphonates, phosphoricacids, aminotrimethylene phosphonic acid,1-hydroxyethylidene-1-1-diphosphonic acid, ethylene diaminetetramethylene phosphonic acid, hexamethylene diamine tetramethylenephosphonic acid, and diethylene triamine pentamethylene phosphonic acid.6. A composition according to claim 5, in which the film-forming binderis selected from the group consisting of homopolymers and copolymersobtained from unsaturated monomers.
 7. A composition according to claim6, in which the unsaturated monomers are selected from the groupconsisting of: vinyl, acrylic, styrene, dienic, halogenated ornon-halogenated monomers.
 8. A composition according to claim 1, furthercomprising at least one additive selected from: pigment additives; andwetting agents.
 9. A method for protecting metal articles againstcorrosion, comprising at least one step consisting in applying to themetal articles a composition according to claim
 1. 10. A methodaccording to claim 9, which does not comprise any anticorrosiontreatments of phosphating and chromating prior to applying to the metalarticles a composition according to claim
 1. 11. A method according toclaim 9, which comprises at least one step wherein metal articles aresubjected to coarse brushing prior to the application of the compositionaccording to claim
 1. 12. A method according to claim 9, which comprisesat least one step wherein metal articles are subjected to coarsecleaning prior to the application of the composition according to claim1.